1. Field of the Invention
The present invention relates to a three-dimensional vision camera for photographing a three-dimensional image.
2. Description of the Prior Art
As a method to observe a three-dimensional image, three-dimensional vision is known: a two-dimensional image is shot by a camera and information on the distance to the photographic object is obtained to produce a three-dimensional vision signal. The three-dimensional image is reproduced on a three-dimensional vision screen.
Referring to FIG. 1, there is shown the arrangement of a conventional three-dimensional vision camera for producing a three-dimensional vision signal. This three-dimensional vision camera is provided with an image sensor 51, a distance measurer 52 and a synthesizer 53. The image sensor 51 including a taking lens 54 and a charge coupled device (CCD) 55 serving as a light receiving element directs a light beam from a photographic object 50 to the CCD 55 to perform photographing. The CCD 55 converts the received light beam into an electric signal and outputs it as a video signal.
The distance measurer 52 including a light emitting diode (LED) 56 serving as a light emitting device and a photodiode array 57 serving as a light receiving device irradiates a light beam from the LED 56 to the photographic object 50. The reflected light beam is received by the photodiode array 57. In front of the LED 56, a lens 58 is provided for directing the irradiated light beam to the photographic object 50. In front of the photodiode array 57, a lens 59 is provided for directing the reflected light beam to the photodiode array 57. The photodiode array 57 converts the received light beam into an electric signal and outputs it as a distance signal. The distance to the photographic object 50 is detected based on the light received position on the photodiode array 57.
The synthesizer 53 produces a three-dimensional vision signal from the video signal from the CCD 55 and the distance signal from the photodiode array 57 and outputs the three-dimensional vision signal. The three-dimensional vision signal thus produced is transmitted to a three-dimensional vision screen (not shown) to display a three-dimensional image.
In the three-dimensional vision camera of the above-described arrangement, the image sensor 51 and the distance measurer 52 are separately provided and the photographing and the distance measurement are performed by the two individual optical systems. Thus, the image, i.e. two-dimensional information (x and y vectors) and the distance information (z vector) are obtained by the different optical systems, so that a disagreement is caused between the x and y vectors and the z vector. When the distance between the image sensing optical system and the distance measuring optical system is large, the disagreement between the vectors increases, so that the three-dimensional image displayed on the three-dimensional vision screen is unnatural. The reduction in distance between the image sensing and distance measuring optical systems is limited in the arrangement where the image sensor and the distance measurer are separately provided, so that it is impossible to produce a three-dimensional vision signal in which the vectors completely agree with each other.